The complete Salvia Guide
Common name: Sage
Latin name: Salvia
Height: from 20 to 200cm
Aspect: Sun or partial shade
Soil Type: Well Drained/ No sitting water
Flowering Period: Spring to Autumn
Hardiness: Frost hardy to -7
RHS Hardiness Rating: H2 to H5
Types of Salvia
Salvias have fast become very popular with its long period of flowering, May – September even into October. The best time to plant out salvias is from late April May to early June, or as soon as possible after the risk of late spring frosts have passed. Giving your plants the maximum time to establish and get their roots down before winter. If you purchase your plants late in the season, they are best kept frost free and planted out the following spring.
The genus of salvia contains over 900 species. They are members of the `lamiaceae’ or mint family or lip flowering. Traditionally sage as it is also known was used as herbs for its beneficial and medicinal properties.
Over the years many flowering varieties from Mexico, Central and South America and Southern states of the USA have become popular with a lot of European countries such as the UK because of their considerable long flowering period and diversity in flowers and leaf shapes.
They are also very good pollinators which are regularly visited by bees, bumblebees, moths and humming birds in tropical climates.
Many experts / growers place salvias into 3 categories which are listed below, determined mainly by their winter hardiness.
Types of salvia variety
- Hardy Herbaceous (up to -22°C)
- Hardy bushy salvia’s (up to -8 ° C to -12 ° C)
- Semi-winter hardy and frost sensitive salvia`s (0 °C to -8 °C)
How to grow salvias
Soil conditions are very important in getting the best from your Salvias, A light free – draining soil in full sun is the ideal spot. In colder parts of the country, find a sheltered spot, such as next to a sunny, south-facing wall.
Salvias don’t require rich humus soil, but like us all they would benefit from a good feeding, I would recommend a scattering of general feed in late spring. They would also benefit from a liquid feed throughout the summer months, high potash would produce more flowering. Salvias can always be planted in tubs and pots giving a riot of colour on any patio throughout the summer, John Innes number 3 would be a suitable compost. Salvias are drought tolerant, so are an especially good choice in areas of low rainfall.
Time of year to plant: best time to plant out is in the spring and early summer so that they develop a strong root system to go into the winter. Semi-hardy species are best kept in a warm and protected place from the northeast wind. Most salvia’s keep full sun, yet there are exceptions. The larger the leaf, the more shadow they can endure.
Repeat a second decent pruning mid July and you will get exuberant autumn blooms.
Prune hard late spring as the new growths appear, Cut all the dead foliage from the winter just above the new growth. Within a few weeks, the plant will be bursting into colour, flowers will start to appear from late April onwards. As the plant feels tied mid/ late summer prune again which will stimulate new growths of foliage and flowers well into the Autumn. These are great easy growing varieties to get you hooked on the Salvia collecting experience.
Never completely prune them in the winter. At the beginning of April you can cut the plants down to 1/3 once they are shooting
Salvias usually attract two types of bugs: greenfly and capsid bugs. To eliminate greenfly, use soapy water over the leaves. To treat capsid bugs use provado which is very important to do as it can cause distorted growth
Hardy Herbaceous (up to -22°C)
We can generally say these are regarded as fully hardy salvias, variety’s such as salvia nemorosa, s. verticillate, s. pratensis s. sylvestris. These plants can be left outside and they will survive the winter.
Hardy bushy salvia (up to -8 ° C to -12 ° C)
This group contains some of the most popular varieties such as microphylla, greggii, and x jamensis. They bloom in full sun from May to November. These survive most reasonable winters in England. Always add some leaf mould round the base during hard winters to give extra protection. A slight pruning in late summer helps stimulate further flowering until the frosts. Hybrids such as involucrate, guaranitica and uliginosa are also hardy in some areas of the country.
Semi-winter hardy and frost sensitive salvia (0 °C to -8 °C)
This group contains a lot of the Latin American and Californian varieties. These will need protection over the winter in greenhouses or cold frames keeping the frosts out. Take some cuttings as a precautionary measure and keep frost free. A lot of the new love and wishes range are not hardy and will need protection.
Cutting should be taken in August or September which gives lots of new plants that you can plant in your garden or give away.
- When taking cuttings, it is important you pick a stem with at least with three nodes. While two nodes work fine, cutting from a stem with three nodes will ensure that the cutting will grow into a larger and more prolific plant.
- Once you have located a stem for the cutting use secateurs to cut the stem just below the bottom node. These nodes contain a particular plant growth hormone, auxin, which induces both leaf and root growth.
- Once you have your cutting the next step is to dip the salvia cutting into a rooting hormone as this will encourage faster growth of new roots in the next few days.
- Place the cuttings in a well-draining soil. Make sure that the plants receive full sunlight – preferably on the south-facing location. Water the cutting and cover the pot with a clear, plastic bag to protect them from strong winds.